History of the Term UFO

The term UFO came into being during the time of the U.S. Air Force’s investigation of flying saucers. During Project Grudge which later turned into Project Bluebook the term UFO replaced the word Flying Saucers this was in the year 1949.

The best definition for the word UFO, which stands for Unidentified flying Objects was given by the late Dr. Hynek. For 20yrs Dr. Hynek was the official astronomy consultant for project Bluebook. His definition of a UFO is this; “the reported perception of an object or light seen in the sky or upon the land the appearance, trajectory, and general dynamic and luminescent behavior of which do not suggest a logical, conventional explanation and which is not only mystifying to the original percipients but remains unidentified after close scrutiny of all available evidence by persons who are technically capable of making a common sense identification, if one is possible."

Ref: UFOcasebook.com